<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style type="text/css">
        body {
            background-color: #ccc;
        }

        #app {
            width: 400px;
            margin: 20px auto;
            background-color: #fff;
            border: 4px solid blueviolet;
            border-radius: 1em;
            box-shadow: 3px 3px 3px rgba(0, 0, 0, 0.5);
            padding: 1em 2em 2em;
        }

        #app h3 {
            text-align: center;
        }

        #app .title {
            display: flex;
            justify-content: space-between;
            align-items: center;
            border: 1px solid #ccc;
            padding: 0 1em;
        }

        #app .title h4 {
            line-height: 2;
            margin: 0;
        }

        #app .container {
            border: 1px solid #ccc;
            padding: 0 1em;
        }

        #app .btn {
            /* 鼠标改成手的形状 */
            cursor: pointer;
        }
    </style>

</head>

<body>
    <div id="app">
        <h3>案例：折叠面板</h3>
        <div>
            <div class="title">
                <h4>芙蓉楼送辛渐</h4>
                <span @click="isShow = !isShow" class="btn"> 
                    {{ isShow ? '收起' : '展开' }}
                </span>
            </div>
            <div v-show="isShow"  class="container">
                <p>寒雨连江夜入吴,</p>
                <p>平明送客楚山孤。</p>
                <p>洛阳亲友如相问，</p>
                <p>一片冰心在玉壶。</p>
            </div>
        </div>
    </div>

    <script src="./vue.js"></script>
    <script>
        new Vue({
            el: '#app',
            data: {
              isShow: true
            }
        })
    </script>
</body>

</html>